Inspection hole closure assembly



1968 K. K. MASON INSPECTION HOLE CLOSURE ASSEMBLY Filed Sept. 19, 1966 yum 52 i7 ms mwmw N454, w J, wKm

an w 2 Claims. CI. 52-20 ABSTRACT OF THE DISCLOSURE A manhole cover assembly wherein a manhole is supported by a support ring which is in turn supported by an adjustment support segment within the outer base member of the assembly, the cover and support ring height being varied'to suit road variations by replacement of the segment, and the manhole cover being prevented from rocking by a depending flange engaging the support ring, the support ring in turn engaging the inner walls of the outer base member.

This invention relates to an assembly for the closure of an inspection hole in a road or other ground surface.

It is customary for underground services to have access through inspection holes for example, manholes, and the convenient locations for many inspection holes are in road surfaces. This gives rise to considerable problems when a road subsides or is to be top-dressed, in that the inspection hole cover either projects above the road surface or is disposed below the road surface, and the main object of this invention is to provide means whereby the inspection hole cover can be readily positioned or repositioned so that its upper surface is co-planar with the road surface.

It will be realised that manhole covers must carry a substantial weight and also the drive or braking of vehicles can exert heavy rotational forces on them, and this is aggravated where the cover is too high or too low in relation to the road apart from the inconvenience of shock to the vehicle should it pass over such a badly fitting cover.

At the present time it is necessary to remove the base member which is permanently fixed into the road to act as a holder for the cover and to then re-set this, and the object of this invention is to overcome the above difiiculties by so arranging the manhole cover assembly that exact alignment of the cover and its holding mechanism can be effected in relation to the roads surface without it being necessary to re-position the base member which is a fixture in the roads surface itself.

It is a further object to so arrange such a cover that the problem of rocking or rotation of the cover under heavy loading does not take place, because if this is permitted to happen induced wear between adjacent parts at some localities and dust build up at others will give uneven setting with consequent problems.

A further object is to provide means for ready removal of the cover holding structure when an adjustment of height is necessary.

The objects of the invention are achieved by forming a manhole closure assembly to comprise a base member fixed into the roadway itself, and positioned within this base member an internally open support member which can be raised and lowered to required heights in relation to the main base member, a manhole cover engaging in this latter adjustable section, adjusting means being provided to hold the support member at a required height in relation to the base member.

To enable the invention to be fully understood it will United States Patent F on line 3-3 of FIG. 1,

, 3,408,778 Patented Nov. 5, 1968 now be described with reference to the accompanying drawings which show some embodiments thereof-but it is to be clear that the invention need not necessarily be limited to these, the ambit of the invention being defined in the accompanying claims.

In the drawings:

FIG. 1 is a transverse section of a manhole coverassembly according to this invention,

FIG. 2 is a corresponding view but showing how by the use of a spacing adjustment segment the manhole cover is raised in relation to its supporting base,

FIG. 3 is a part sectional plan with a section taken as FIG. 4 is a section as on line 4- 4 of FIG. 3 and FIG. 5 shows a modified form of construction, the view corresponding generally to FIG. 1.

According to the embodiment shown in FIGS. 1 to 4 the manhole base 1, which is adapted'to be positioned on a suitable support or is otherwise fixed into a road surface to give access to a surface which the manhole serves, has on it an external locating flange 2 and an internal supporting flange 4 which forms an upper shoulderwithin a recess also into which is fitting a manhole cover support ring 5. Q

The manhole cover support ring 5 has a shoulder 6 on it on which the outer annular flange 7 of a manhole cover 8 rests.

The manhole cover support ring 5 is held to the supporting flange 4 of the base 1 by threaded studs 9 which pass through apertures in the ring 5 and screw into threaded apertures in the supporting flange 4.

In FIG. 1 is shown how the device is used when no adjustment between the base 1 and the manhole cover 8 is required.

In FIG. 2 is shown how an adjustment segment 10 can be disposed between the lower face 11 of the support ring-5 and the face 12 on the supporting flange 4 of the base 1.

By adjusting the thickness of the adjustment segment obviously the relationship of the support ring 5 to the base 1 can be varied, and therefore the height of the manhole cover 8 which is supported on the face 6 can similarly be adjusted.

It will of course be realised that when a unit is installed it can conveniently be in the form shown in FIG. 2 with an adjustment segment in place so that if the road level falls the adjustment segment can be removed or replaced by a thinner one but if the road level rises adjustment segments can be added, or a thicker segment can replace the previous one, it being obvious of course that the device can be installed with a standard adjustment segment in place and thinner or thicker segments will then give an adjustment both up and down of the manhole support ring 5 and consequently of the manhole cover 8 through it resting on the register pad.

The length of the securing studs will be varied to suit the thickness of the adjustment segment 10. The expression segment includes single or multiple piece members.

The studs 9 are of course accommodated in recesses 16 so that their heads are clear of the manhole cover, and threaded apertures 14 are provided in the manhole support ring 5 to allow ejector studs to be screwed in to lift the ring 5 from position when a segment is to be removed or replaced.

Register pads 15 extend down from the flange 7 to coincide with the recesses 16 for the studs 9 to prevent rotation of the manhole cover 8.

According to the embodiment shown in FIG. 5 a manhole base 20 is positioned on the upper end of a tubular concrete support member 21 which extends downwardly from the ground surface to the service (not shown) which the manhole is required to provide access for. The manhole base 20 has an annular supporting flange 22 which forms the shoulder on which the adjustment support-segment 23 rests. The manhole cover 24 is disposed on the face 25, but the manhole cover has a depending flange 25 which engages against the inner face 27 of the support ring 5. The flange 26 can be either cylindrical or tapered, but as shown in the drawings slightly tapered to be complementary to a similar taper on the wall 27. In the event of failure of the rim of the cover 24, the flange 26 will support the cover by engagement on the support segment 23.

The thickness of the support segment 23 and its shape is varied to meet the requirements of the road surface, and the thickness is adjusted so that the upper surface of the manhole cover 24 is co-planar with the road surface 29. I

The adjustable support member 22 in having its upper surface co-planar with the road surface and the manhole cover provides an arrangement which can prevent the possible adhesion of bituminous compounds or the like to the edges of the manhole cover 24.

Threaded securing studs 28 are employed to retain the adjustable support segment 23 in position on the base 20, this ensuring against relative displacement, which, as is well known, may result in wear and build-up of dust between adjacent surfaces. At the same time it will be seen that the depending wall 26 of the manhole cover 24 in engaging the inner wall 27 of the support member 22 also prevents damaging rocking of the manhole cover] What I claim is:

1. A manhole cover assembly comprising a base member adapted to be embedded in a road beneath the road surface and having an inwardly extending supporting 4 flange and a vertically extending alignment flange, an annular adjustment segment on the supporting flange, a manhole support ring on the Segment having vertically directed concentric inner and outer walls, bolts extending through. the supporting flange, segment and ring retaining the ring to thesupporting flange, a manholecover in and supported by the support ring, a vertically depending flange on the manhole cover, cooperating engaging and supporting wall configuration between the alignment flange on the manhole cover, a cooperating engaging and and also between the inner wall of the ring andgthe depending flange of the manhole coven. V p I;

2. A manhole cover assembly accor ing to clairn 1 wherein said support ring further comprises an inner upper recess and wherein said manhole' c ove ri further comprises an outer annular flangeenga'ge'd in' the recess .lhereby. supporting the cover, and; the. up per; 'su rfa'ce v of said segment is disposed below and positioned beneath the lower end of said depending flange of the manhole cover thereby providing secondary support means for themanhole covers upon failure ofsaid outer annular flange thereof. a I i i l References Cited I UNITED STATESPATENTS .j. 2

525,101 10/1894 Greger 94-34 1,766,621 6/1930 Fleming 94 34 1,898,871' 2/-1933"Ellis 9445 'Sorrell 94-34 FRANK L. ABBOTT, Primary Examiner.

D. BURKE, Assistant Eicam'iner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3,408, 778 November 5, 1968 Keith K. Mason It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 8, before "cooperating" insert a line 9, "on the manhole cover, a cooperating engaging and" should read of the base member and the outer wall of the ring Signed and sealed this 3rd day of March 1970.

(SEAL) Attest:

Edward M. Fletcher, Jr. WILLIAM E. JR.

Attesting Officer Commissioner of Patents 

